High-Temperature and High-Energy-Density Dipolar Glass Polymers Based on Sulfonylated Poly(2,6-dimethyl-1,4-phenylene oxide)

A new class of high-temperature dipolar polymers based on sulfonylated poly(2,6-dimethyl-1,4-phenylene oxide) (SO₂-PPO) was synthesized by post-polymer functionalization. Owing to the efficient rotation of highly polar methylsulfonyl side groups below the glass transition temperature (T_g≈220 °C), the dipolar polarization of these SO₂-PPOs was enhanced, and thus the dielectric constant was high. Consequently, the discharge energy density reached up to 22 J cm⁻³. Owing to its high T_g , the SO₂-PPO₂₅ sample also exhibited a low dielectric loss. For example, the dissipation factor (tan δ) was 0.003, and the discharge efficiency at 800 MV m⁻¹ was 92 %. Therefore, these dipolar glass polymers are promising for high-temperature, high-energy-density, and low-loss electrical energy storage applications.